Drying method and condensation dryer comprising a heat pump and system for recognizing an unallowable operating state

Abstract

A condensation dryer is provided that includes a drying chamber for items to be dried; a process-air circuit having a first fan; a heat pump in which a coolant circulates; an evaporator; a compressor; a condenser; a throttle; a temperature sensor to measure a temperature of the coolant; a cooler for the heat pump; and a controller. The condensation dryer further includes a comparator to compare the measured temperature of the coolant to a limit temperature that is stored in the controller and to switch on and operate the cooler during a period of time if the measured temperature of the coolant is equal to or greater than the limit temperature. The condensation dryer also includes an evaluator to evaluate a change in the measured temperature of the coolant during the period of time with regard to a non-permitted operating state of the condensation dryer.

1 - 16 . (canceled) 
     
     
         17 . A condensation dryer, comprising:
 a drying chamber for items to be dried;   a process-air circuit having a first fan;   a heat pump in which a coolant circulates;   an evaporator;   a compressor;   a condenser;   a throttle;   a temperature sensor to measure a temperature of the coolant;   a cooler for the heat pump;   a controller;   a comparator to compare the measured temperature of the coolant to a limit temperature stored in the controller and to switch on and operate the cooler during a time period if the measured temperature of the coolant is equal to or greater than the limit temperature; and   an evaluator to evaluate a change in the measured temperature of the coolant during the time period with regard to the presence of a non-permitted operating state of the condensation dryer.   
     
     
         18 . The condensation dryer of  claim 17 , wherein the compressor has a compressor output and the condenser has a condenser output, and wherein the temperature sensor is at one of the compressor output and the condenser output. 
     
     
         19 . The condensation dryer of  claim 17 , wherein the cooler has a heat exchanger in the heat pump. 
     
     
         20 . The condensation dryer of  claim 19 , wherein the heat exchanger is in a process-air channel between the evaporator and the condenser. 
     
     
         21 . The condensation dryer of  claim 19 , wherein heat exchanger is in a cooling-air channel. 
     
     
         22 . The condensation dryer of  claim 17 , wherein the cooler has a second fan. 
     
     
         23 . The condensation dryer of  claim 22 , wherein the second fan is in at least one of a cooling-air channel and a vicinity of the compressor. 
     
     
         24 . The condensation dryer of  claim 17 , further comprising at least one of an acoustic indicator an and optical indicator to indicate the non-permitted operating state of the condensation dryer. 
     
     
         25 . A method for operating a condensation dryer, the condensation dryer having a drying chamber for items to be dried, a process-air circuit, a first fan in the process-air circuit, a heat pump in which a coolant circulates, an evaporator, a compressor, a condenser, a throttle, a temperature sensor to measure a temperature of the coolant, a cooler for the heat pump, a controller, a comparator to compare the measured temperature of the coolant to a limit temperature stored in the controller and to operate the cooler during a time period if the measured temperature of the coolant is equal to or greater than the limit temperature, and an evaluator to evaluate a change in the measured temperature of the coolant during the time period with regard to the presence of a non-permitted operating state of the condensation dryer, the method comprising:
 if the measured temperature of the coolant is equal to or greater than the limit temperature, switching on the cooler and operating the cooler for the time period; 
 determining a temperature difference between a first temperature measured at the temperature sensor when the cooling device is switched on and a second temperature measured at the temperature sensor after operating the cooler for the time period; and 
 evaluating the temperature difference with regard to determining the non-permitted operating state of the condensation dryer. 
 
     
     
         26 . The method of  claim 25 , wherein a first non-permitted operating state is indicated if the temperature difference is equal to or greater than a first predefined value. 
     
     
         27 . The method of  claim 26 , wherein the indication of the first non-permitted operating state includes an instruction to clean airways in the condensation dryer. 
     
     
         28 . The method of  claim 25 , wherein a second non-permitted operating state is indicated if the temperature difference is equal to or greater than a second predefined value. 
     
     
         29 . The method of  claim 28 , wherein, in addition to indicating the second non-permitted operating state, a drying process in progress is interrupted. 
     
     
         30 . The method of  claim 25 , wherein the switching on of the cooler includes switching on a second fan. 
     
     
         31 . The method of  claim 30 , wherein the second fan and a heat exchanger are in a cooling-air channel. 
     
     
         32 . The method of  claim 31 , wherein the heat exchanger is in the heat pump.